Hire the Best Android SDK Specialists

Top Rated Plus | $200K+ Earned on Upwork | 100% Job Success | 10+ Years on Upwork I'm an Android Developer and Mobile App Developer with 12+ years of professional experience and a PhD in Computer Science. With $200K+ earned, 100% Job Success, and Top Rated Plus status on Upwork for 10+ years, I build production-ready Android and mobile applications that scale, not MVPs that fall apart under real user traffic. As an Android Developer, my core work covers native Android App Development in Kotlin and Java, full-lifecycle delivery from requirements and architecture through Google Play release, and backend integration with REST APIs, Firebase, AWS, and third-party services. I've shipped apps with 1M+ downloads. As a Mobile App Developer, I also deliver cross-platform solutions using React Native and Flutter when a project needs iOS and Android from a single codebase. As an Android Developer and Mobile App Developer, I've delivered across fintech, healthcare, logistics, social networking, sports, e-commerce, fitness, and entertainment. I also have extensive experience in healthcare and safety applications where data encryption, secure messaging, and compliance are non-negotiable. My architecture approach as an Android Developer is Clean Architecture with MVVM and MVP patterns, Kotlin Coroutines and Flow for async tasks, Hilt for dependency injection, and Jetpack Compose for modern UI. I use RxJava where legacy codebases require it and maintain CI/CD pipelines with Jenkins and TeamCity to keep releases reliable and predictable. As a Mobile App Developer and Kotlin developer, I take ownership of API planning with backend teams, code reviews, refactoring, and full technical documentation so the codebase remains maintainable long after delivery. I work as part of a team at Requestum, which means I can bring in backend, iOS, or QA specialists when a project needs more than one mobile app developer to ship on time. Clients typically work with me when they need: - an Android Developer to build a native Kotlin app from scratch to Google Play release - a Mobile App Developer to deliver iOS and Android from a single React Native or Flutter codebase - an Android App Developer to refactor, optimize, or extend an existing Kotlin or Java codebase - a Kotlin developer who understands Clean Architecture and can own the full technical roadmap - a mobile app developer with experience in fintech, healthcare, logistics, or social platforms If you need an Android Developer who ships production-grade apps and takes full technical ownership, let's talk. Main stack: Kotlin, Java, Android SDK, Jetpack Compose, Android Jetpack, Hilt, Kotlin Coroutines, RxJava, Retrofit, Firebase, AWS, Google Maps API, Stripe, React Native, Flutter, Room, Realm, Jenkins, Docker.

Need a fast, scalable iOS app built with SwiftUI — or help fixing a messy codebase? I help startups and growing companies build production-ready iOS apps with clean architecture, smooth performance, and App Store–ready polish. Recent results: 🚀 Top 100 Kids Paid app on the App Store 💰 $400K+ earned | 10,500+ hours on Upwork ✅ 200+ successful projects with long-term clients 💡 What I can help you with: SwiftUI & UIKit app development (from MVP to scale) Refactoring and modernizing legacy iOS codebases Subscription systems & In-App Purchases Performance optimization & architecture improvements API integration & scalable backend connectivity App Store submission, compliance & launch support 🎯 Who I work best with: Startups and teams that need a reliable senior iOS developer who thinks beyond code — focusing on scalability, performance, and long-term product quality. If you want clean code, clear communication, and fast execution — let’s talk.

Dear Sir/ma'am, I am an expert Mobile app developer and developed 35+ apps having millions of users and downloads. I have developed a wide range of mobile apps. Solana Wallet based app Beacon/Hardware devices based apps Chat app Taxi app Social app Offer & Coupon Based app Restaurant Based App Messenger App Printer Based App Beacon Estimote based app Photo editing app e-Book Reader Based App Using my Experience and Knowledge to provide 100% Guaranteed Service Blended with Quality and Accuracy. Iím an Expert, Honest, Sincere and Responsible Contractor. Looking for the next opportunity to prove my Expertise and to make a Long Term Successful Relation with my Employer.

From concept to launch, I build production-grade mobile applications that are scalable, secure, and built to deliver real business results. I’m Hardeep, an experienced Mobile App Developer with over 10 years of hands-on expertise creating high-performance mobile apps for startups and enterprises. I specialize in native iOS and Android development, as well as React Native, with a strong focus on AI-driven features and modern app architectures. Whether you’re launching an MVP or scaling an existing product, I help transform ideas into reliable, user-friendly mobile experiences that perform exceptionally well in real-world conditions. ==> Mobile Development Expertise: ------------------------------------------ I work extensively with iOS (Swift), Android (Kotlin), React Native, and Flutter to build fast, responsive, and maintainable mobile applications tailored to your business goals. ==> AI-Driven Features & Integrations: --------------------------------------------- I integrate AI capabilities such as LLM APIs (GPT, Llama), conversational AI, and predictive models to enhance user engagement, automation, and decision-making within mobile apps. ==> Industry Experience: ------------------------------ I have delivered successful solutions across multiple domains, including FinTech, Healthcare (HIPAA-compliant apps), video streaming, subscription-based platforms, social and dating apps, and real estate solutions. ==> Payments, Streaming & Infrastructure: -------------------------------------------------- My experience includes payment gateway integrations (Stripe, PayPal, Apple Pay, Google Pay), subscription systems, in-app purchases, and real-time video streaming using WebRTC, Twilio, Zoom, and Agora. I also handle CI/CD pipelines, app distribution, and cloud-backed mobile infrastructures. ==> How I Work: ------------------- I follow Agile development practices, prioritize clear communication, and provide regular updates throughout the project lifecycle. My code is clean, scalable, and designed to support long-term growth and future enhancements. If you’re looking for a reliable mobile app developer who understands native and cross-platform development and can seamlessly integrate AI-powered features, I’d be glad to collaborate. Let’s build a high-performing mobile app that users love and businesses trust.

40 Projects Completed | 5 start rating | 100% Job Success Score | Top Rated 🏅 Senior Mobile Developer with experience architecting and delivering complex, business-aligned mobile-first systems and MVPs - taking full ownership from initial concept through scalable production using AI tools like Claude and Gemini for accelerated development. Specialised in both Android and iOS Native for maximum performance and the smoothest app experience with pixel-perfect UIs. Clients rely on my business-first approach: rapid launches powered by intelligent AI workflows, strategic guidance rooted in clean, robust code, and scalable technology that evolves with their long-term goals. 🚀 Tech Stack & Tools: 🛠️ AI & AI Integration: Gemini API, Claude API, OpenAI API (ChatGPT) AI-powered feature development and smart app integration 🛠️ Mobile Development: Kotlin, Jetpack Compose, Swift, SwiftUI Native Android & iOS development 🛠️ Backend & APIs: Firebase (Auth, Firestore, Cloud Functions), REST APIs, third-party integrations, deep linking, push notifications 🛠️ Architecture & Engineering: Clean Architecture, MVVM, performance optimization, scalability, App publishing (Google Play & App Store) 🛠️ Product Design: Figma Pixel-Perfect UI implementation, Figma to Code Why Partner with me? I will take you all the way from idea to first revenue, so you don't juggle specialists - perfect for any founder needing rapid, scalable MVPs that support marketing, analytics & growth. 100% IP handoff, fluent English, and collaborative via Slack/Jira. Let’s catch up and focus on what matters for your first release. Nikola Gocić ___________________________________________________ EXPERTISE: Native Android Development | Native iOS Development | Kotlin | Jetpack Compose | Swift | SwiftUI | Firebase Integration | AI Integration | OpenAI | Gemini | Claude | REST API Integration | Clean Architecture | Figma to Code | Push Notifications | Deep Linking | App Publishing | Google Play Store | Apple App Store | Mobile UI/UX Design

🏆 𝗧𝗢𝗣 𝗥𝗔𝗧𝗘𝗗 𝗣𝗟𝗨𝗦 🏆 ✅ Mobile App Developer 7+ years of experience ✅ SaaS Mobile App Developer 5+ years ✅ 35 mobile app development jobs completed successfully ✅ Android and iOS Mobile Expert ✅ Built 27+ UX-first Mobile App development jobs for 22 companies ✅ On-Time and Cost-Effective Delivery ✅ Future-Proof Solutions Showing a Minimum 41% ROI ✅ 4354 mobile app development hours on Upwork and still counting ✅ 100% Job Success in mobile app development (Client Satisfaction Ratio) ✅ 98% of Clients Recommended working with me ✅ 80% Long-term Repeat Clients ✅ 7+ years of experience in mobile app development, 6 years experience in iOS mobile app development, 7 years experience in Swift and Kotlin, 4 years experience in Flutter, React Native, 2 years experience in KMM, KMP Full stack mobile app developer and mobile app UI UX designer with 7+ years of experience in Mobile App Development, specializing in iOS, Swift, Android, Kotlin, KMM, Kotlin Mutliplatform / KMP, React Native, and Flutter. I have successfully delivered 120+ mobile applications in different roles as mobile app developer, flutter app developer, flutter full stack developer, flutter flow, mobile app design, mobile ui ux designer, swift ios developer, android developer, kotlin developer, react native developer, mobile game developer achieving a 5-star rating on Upwork and helping clients scale their businesses with high-performance solutions. Apart from mobile app development, I specialize in Mobile App Design for both iOS and Android, as well as Web App Design for SaaS platforms. My expertise extends to Interaction Design, User Flow Design, and creating seamless User Experience (UX Design) and User Interface (UI Design). I follow a Design Thinking approach, ensuring every solution is user-centered and problem-solving. My process includes UI/UX Wireframing, Prototyping, and building Style Guides or UI-kits for consistent branding. I perform Design Audits and Design QA to maintain high standards across all projects. 🛠️ Design Tools: My designs come to life through powerful tools like Figma, Zeplin, and InVision for prototyping and collaboration. I leverage Adobe Illustrator, Adobe Photoshop, and Adobe XD for detailed visual design. For complex wireframes and flow mapping, I turn to Axure, Sketch, and Balsamiq. I also use Miro and Abstract for brainstorming and version control, while project communication and management happen in Slack and Jira. Our Expertise at a Glance • Mobile App Development: Android, iOS, & Cross-Platform App Development using Java, Kotlin, Swift, Objective C, Flutter, and more. • Website and Full Stack Development: Crafting seamless back-end experiences with .Net, Python, Java, Javascript, React.js, Angular.js, Node.js, MERN, MongoDB, PHP, etc. • Logo & UI/UX Design: Bringing your ideas to life with Adobe XD, Photoshop, Sketch, Figma, etc. • End-to-End Solutions: From logo design, UI/UX development, workflow setup, testing to deployment in app stores, we've got it all covered. We do not use v0.dev lovable.app CursorAI, Cursor, Windsurf, Trae, GitHub Copilot, Tabnine, Qodo, Devin AI, and AutoDev for speed up coding, we know other methods to do it efficiently. We offer a comprehensive range of development services across mobile, web, and cloud platforms. Our mobile app development expertise includes building Android and iOS applications using technologies such as Flutter, Swift, Objective-C, React Native, and Xamarin, optimized for both smartphones and tablets with a focus on cross-platform compatibility. In website and full stack development, we work with .NET technologies, including full stack .NET development, .NET Core, and Python with Django. Our team is experienced in developing both backend systems and user-friendly, responsive web interfaces, as well as working with various CMS platforms. Our DevOps and DevSecOps capabilities cover cloud infrastructure and automation, leveraging tools like AWS, Azure, Docker, Kubernetes, GitLab CI, Ansible, and Terraform to build secure and scalable deployment environments. We also build cross-platform and web applications using frameworks like Three.js and design tools such as Webflow, creating visually engaging and functional user experiences across devices. Additionally, we are well-versed in integration and automation tools, including WebSockets, data integration, the ABP Framework, Discord API, and Autotask, allowing us to create seamless connectivity and workflow automation between systems. Talent Good Knowledge, Talented, Experienced, Skilled, Strong Experience, Proven Experience, Agency, Team, Company, Specialist, Proven Track Record, Strong Background, Write Clean Code, Deep Expertise, Bring to Life, Cross-platform, Attention to Detail, Long Term. ⚡️ AVAILABLE FOR NEW PROJECTS ⚠️ Press Invite Button on my page and let's talk.